Detachable relay



' June 9, 1942. p, T E 2,286,044

DETACHABLE RELAY Filed March 25, 1959 2 Sheets-Sheet 1 INVENTORS. Charles P. West Bay M. Smith and William A.Le is,Jr.

June 9, 1942.

C. P. WEST ET AL DETACHABLE RELAY Filed March 23, 1939 2 Sheets-Sheet 2 Patented June 9, 1942 2,286,044 DETACHABLE RELAY Charles P. West, Forest Hills, Pa., Roy M. Smith, Livingston, N. 1., and William A. Lewis, .lr., Ithaca, N. Y., assignors to Westinghouse Eiectrio & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania I Application March 23, 1939. Serial No. 263,722

11 Claims.

Our invention relates to detachable instruments, and it has particular reference to means. for preventing incorrect operation of detachable instruments during attachment and removal thereof.

Because of the facility with which detachable instruments may be removed, serviced, adjusted and replaced, a detachable construction is highly desirable for relays and similar instruments. When employed for sensitive relays such a construction may result in incorrect operation of the relay during attachment and removal thereof because of the tendency of these relays to close their contacts under the vibration incident to such removal or attachment. The incorrect operation of the relay would result in improper actuation of the circuit breaker or other equipment controlled thereby,,and such improper operation is highly objectionable.

In accordance with our invention, incorrect operation of a detachable relay or other detachable instrument is prevented by including in the controlcircuit thereof a switch or other control element which must be actuated before the detachable relay or instrument can be removed and It is, therefore, an object of our invention to render the control means of a detachable instrument ineffective prior to removal thereof.

It is another object of our invention to provide a relay having a control circuit with means for opening said circuit prior to removal of the detachable relay. I

It is stillancther object of our invention to provide a detachable instrument with fastening means and a control element responsive to the condition of the fastening means. It is a still further object of our invention to provide a detachable relay having means for rendering the relay contacts of a relay energized from a current transformer ineffective prior to removal of the relay from its base and having circuit completing means for short circuiting the current transformer.

Further objects of our invention will be apparent from the following description taken in conjunction with the accompanying drawings, in

- which:

the relays shown in Figs. 2 and 3.

Fig. 4 is a view in side elevation of a switchboard relay embodying ourinvention;

Fig; 5 is a view in side' elevation with parts broken away of a modification of the structure shown in Fig. 4;

Fig. 6 is a detail view in section of a further modification of the structure shown in Fig. 4;

Fig. 7 is a fragmentary view in front elevation I of the relay structure shown in Fig. 8; and

Fig. 8 is a diagrammatic view'of an electrical circuit embodying a modified control designed in accordance with our invention.

Referring to the drawings, Fig. 1 shows one conductor. i of an electrical circuit to be protected. Protection of this circuit is effected by means of a circuit breaker 2 having a solenoid control 3 for tripping purposes. Actuation of the circuit breaker is effected by means of a relay 4 which has an operating coil 5 actuated from the conductor, I through a current transformer 6. The relay 4 also includes a pair of contacts 1 which are included in a local circuit breaker tripping circuit comprising a battery 8 and a trip coil 9. The specific relayillustrated is of the overcurrent type.

As the current flowing through the conductor l increases, it reaches a value sufllcient to actuate the contacts 1 thereby completing a circuit for the trip coil 9 and tripping the circuit breaker 2. If =therelay 4 is of a detachable construction, attachment and removal thereof invariably are accompanied by some vibration of the instrument. Such. vibration in the case of a sensitive relay may be suflicient to actuate the contacts I to their closed position, thereby incorrectly tripping the circuit breaker 2. In order to prevent incorrect operation, it is possible to include in the local circuit a switch l0 which is connected to the trip coil 9 and the contacts 1, respectively, by conductors H and I2. By opening the switch ill prior to removal of the relay, the condition of the contacts I has no further eflect upon the actuation of the circuit breaker 2, and the relay 4 may be handled as desired.

Manual operation of the switch II is disadvantageous for the reason that it may not be operated because of carelessness or oversight on the partv of the operator. For this reason, it is desirable to so interlock the switch I. with the detachable relay that it must be operated before the relay can be detached from its socket. A relay embodying this interlocking desideratum is illustrated in Fig. 2.

In Fig. 2 the relay is contained in a housing I! which is provided with a plurality of detachable contact blades ll, Ila. These contact blades are detachably received in contact jaws ll, lia carried on insulating blocks it which are mounted in a socket i'l. Removal and replacement of the relay are effected by merely lifting the housing 12 and the contact blades carried thereby from the socket and replacing it after desired inspection and adjustments have been-carried out. The socket may be provided with an opening H for receiving a conduit for wiring purposes.

In order to secure the relay in place, the housing it and the socket II are provided, respectively, with flanges IO and I 9 which abut each other when the relay is in mounted position. For securing the various parts together, a sealing ring embraces the flanges ll and I! and is attached in place by a bolt 2| which passesthrough suitable clip retaining means 22 on the ring 20. The various parts of the detachable relay structure thus far described may be patterned after the detachable construction for watthour meters disclosed in the Bradshaw et al. patent No. 1,969,499, assigned to the Westinghouse Electric a Manufacturing Company.

As illustrated in Fig. 2, the switch I. is posiof contacts mounted on spring arms 22 and 24. When free, these arms are in the positions depicted by the dotted lines, and the switch consequently is open. Closure of the switch'is effected by means 0! an insulating push rod 25 which slidably passes through a boss 2' formed in the socket II. The push rod 25 is positioned to enage the clip means 22 when the latter is in its attached position. 7

In its attached position, the clip means 22 detioned within the socket l1 and comprises a pair presses the push rod 25 to close the switch III.

the first step is to remove the sealing ring 20. The removal of the sealing ring, in turn, releases the push rod 26, and the switch Hi consequently is placed in its open condition because of the re:- siliency oi the arm 24. position, the relay may be removed from the socket without fear of incorrect operation of the circuit breaker 2. As apparent fromFig. 2, the arm 24 of the switch is connected to the relay contacts through the conductor l2, the contact jaw Hi and the contact-blade ll appearing to the left in Fig. 2. 7

It will be noted from Fig. 1 that the, relay operating coil 5' is connected to a current transformer 8. When the relay 4 is removed'from its socket, unless some provision were made, the current transformer secondary would be open and dangerously ,high voltages would be produced with the switch in open therein. For this reason; we prefer to provide the switch is shown'to the right in- Fig. 2. As

will be apparent from the illustration, the switch i 21 consists of a spring conductive leaf which nor- 75.

snoop mally is biased iii contact with the contact jaw "a. When the contact blade Ila is inserted in the contact jaw, the resultant movement 01 the contact jaw is transmitted through an insulatbig push rod 28 which engages the inner end of maining half of the contact jaw iSa to increase In the modification shown in Fig. 3, the switch II is replaced, by a switch lDa which is actuated by means of a key 30. This key may be withdrawn from the switch only when the switch is in its open position. Conductors Na and Ila-correspond to the conductors II and I2 of Figs. 1 and 2. -The relay 4 in Fig. 3 is retained in position by means of a lock ll which has a bolt 32 engag- 'ing a lug ll afllxed to the relay. The lock ll is actuated by the same key ll employed for theswitch Ila, and the key may be removed from the lock only when the bolt 22 is in its extended or looking position. Consequently, in order to remove the relay from its socket II the key ll must be moved to open the switch Ila, this,oi course.

rendering the relay contacts ineffective. The key ll then may be removed from the switch for insertion in the lock SI, and may be actuated to release the relay 4 from its socket. If desired, the switch ifla may be built into the lock 3| as shown in Fig. 3a so that rotation of the key in one direction opens the switch and retracts the bolt 32. The return of the key to its original position would reclose the switch and advance the bolt to its locking position. 7 Fig. 3a illustrates a socket construction simi lar to that of Fig. 3 except that the switch Ila and the lock 3| are replaced by a corresponding switch M and a corresponding lock Sill. The

switch "it and the lock 310 are associated so.

that a single key I" suffices to actuate both the switch and the lock. Rotation of the key in one direction operatesto extend the bolt 320 of the lock and to close the contacts of the switch I00."

Rotation of the key in the opposite direction operates to retract the bolt 320 and to open the contacts of the switch [00. Except for the substitution of a key for simultaneously operating both the lock and the switch Fig. 3a is similar to Fig. 3. k

The relay constructions thus far described may be adapted either for individual mounting or for switchboard mounting. For switchboard mountings the socket I! would be a part of the switchboard panel.

Another modiilcation illustrated as mounted on a switchboard is shown in Fig. 4. In this figure, a relay 34 is attached to a switchboard panel 35 by one or more bolts 36. The relay :4 is provided with contact blades 31 which pass through openings in the switchboard and engage. contact jaws ll mounted on an insulating panel 30 positioned in the rear of the switchboard panel.

The construction of Fig. 4 is provided with a switch llb and conductors llb and MD corresponding to the switch II and conductors ii and A design suitable for' it of Figs. 1 and 2. 'One of the contacts 43 of the switch ilb is mounted on an insulation block 4i attached to the switchboard panel 35. I The remaining contact 42 is mounted on a lever 43 that is pivoted on a fulcrum 44 carried by the switchboard panel. Insulation 4! is interposed between the contact 42 and the lever 43. Movement of the lever is restricted by a pair of stops 48 and 41 which also are mounted on the switchboard panel. Normally the switch ilb is biased in itsopen position by means of a spring 43 when the relay 34 is detached from the switchboard panel. In order to close the switch ilib and place the relay 34 in operative condition, a bolt 49 is passed through a flange 53 formed on the relay into threaded engagement with the lever 43. Rotation of the screw. 40 into attached position rotates the contact 42 into switch-closing position. It will be noted from Fig. 4 that the relay 34 cannot be removed from the switchboard panel until the bolt 49 has been removed. Removal of this bolt, of course, result in opening of the switch ilb, and this opening renders the relay contacts ineffective.

, Referring to Fig. 5, a modification of the structure shown in Fig. 4 is illustrated, in which a relay 34a, a switchboard panel 35a, contact blades 31a, contact jaws 33a and a sub-panel 33a correspond, respectively, to the elements 34, .33. 31. 3| and 33 of Fig. 4.

In Fig. 5' a switch ilic for rendering the relay contacts ineffectivegcomprises a contact ii attached to the relay 34a and removable therewith, and a contact 32 which is mauled by a lever 53 but insulated therefrom. Aconductor lie is employed for connecting the contact I! to a circuit breaker trip coil and corresponds to the conductor ii of Figs. 1 and 2. The lever 33 is pivotedon a fulcrum'l4 which is-attached to the sub-panel 3la and is restricted in movement by a pair of stops II and I. Normally, the switch lie is maintaihed in closed pomtion by means of a spring I].- The condition of the switch lie is controlled by a Jackscrew II which has a shoulder I3 engaging a flange "a on the relay and which is in threaded engagement with the lever 53. By suitable rotation of the iackacrew 53 the lever 33 is rotated in contact opening direction until it engages the stop ll. Continued rotation of the iaclrscrew 33 then is elective for forcing the relay 34a away from the contact jaws 33a and the switchboard panel 330. The Jackscrew v 53 passes freely through the sub-panel 330.

In many relay units, the number of contacts .required is so large that the frictional engagement of contact blades with contact Jaws makes removal and insertion of the relay difilcult. For this purpose, the Jackscrews 33 may be desirable for forcing the relay 34a from its mounted position against the resistance offered by the contact blades and jaws. If desired, one or more additional jackscrews 530 similar to the Jackscrew 53. may be provided for applying removal force against other portions of the relay structure. Additional screws 33 may be provided for additionally securing the relay 34a to the switchboardpanel 35a.

It should be noted that the lever 43 of Fig. .4 and the lever 53 of Fig. 5 move arcuately relative to the screws 43 and 33, respectively. For

. this purpose, the threaded engagement of each .screw with its lever may be made slightly loose, or'the required movement. may be provided in d any known way.

Fig. 6 includes a relay 34b, switchboard panel 33b. insulating sub-panel 33b, flange 33b and switch iild which cormpond, respectively, to the elements 34, 35, II, II and llb of Fig. 4. The

away from its attached position. These collars engage opposite faces of th flange llbv through which the intermediate portion of the jackscrew passes, the flange being provided with either a contacts 88, 39' are separated.

hole or a notch 31 for receiving the intermediate portion (see Fig. 7) i The switch lld has two contacts I, 03, the

stationary contact 53 being mounted on a post iii which is attached to the sub-panel 33b. A pair of conductors lid, lid, which correspond to the conductors ii, I: of Fig. I connect thecontacts respectively to the relay trip coil and trip contacts in the manner disclosed in Figs. 1 and 4'.

Actuation of the switch ltd is effected through a lever ii which is pivoted on a fulcrum 12 carried by the sub-panel. At one end, the lever carries an insulting block 13 on which one contact 69 is mounted. The opposite end of the lever is provided with an opening I4 for slidably receiving the jackscrew 53b. A switch actuating collar 15 is mounted on the Jackscrew for engaging the lever II and moving the lever in contact closing direction when the jackscrew 53b isrotated to force the relay 34b into its attached position. When the iackscrew is rotated to release the relay 34b, a spring 16 moves the lever Ii into engagement with a stop 11 carried by the sub-panel. In this position of the lever the In the control systems of Flgsl 5 and 6, it

should be noted that the operation of the switch in each case takes place during a very small portion ofthe travel of the jackscrews. Consequently the remaining travel of each jackscrew is employed primarily for controlling the attachment or release of the relay from its supporting base.

, Although in the relay installations thus far,

described the relay contacts normally are in open position and are closed for tripping circuit breakera, for some purposes it may be desired to employ relays having normally closed contacts which are opened for control purposes. For example; in Fig. 8 a relay II is energized from a circuit 32 in accordance with the voltage of the circuit. The relay is provided with a pair of contacts 33 which are maintained in a closed position as long as the voltage remains above a predetermined value. when the voltage of the circuit 3! falls below this predetermined value. the contacts 63 open for control purposes. If it is desired to protect such a relay from' incorrect operation during. detachment, a switch 64 may be connected across the relay contacts.

This switch would be closed prior to removal of the relay in order to prevent inadvertent opening of the contacts 03 from affecting the control circuit.

The relays heretofore described may be modifled readily to provide the sequence of operation called for in Fig. 6. For example, in Fig. 2, the switch it may be so positioned that the push rod 23 engages the arm 33, the arms 23 and 24 being. formed to normally maintain the switch II in closed Position. Depression of the push rod 33 then would tend to open the switch. Similarly, in Fig. 3 the switch Ilia may be designed so that the key '30 can be removed only when the switch is in closed position. Corresponding mod iflcations may be made in the relay constructions illustrated in Figs. 4 and Although we have described our inventionwith respect to certain specific embodiments thereof, it is obvious that numerous modifications thereof are possible. Therefore, we'do not wish our invention to be restricted except as re- I quired by the appended claims when interpreted in view of the prior art.

We claim as our invention:

1. In an instrument unit, a,detachable electrical relay instrument having circuit controlling contact means subject to operation by shock, an instrument base for detachably receiving said instrument, a circuit controlled by said instrument,

switch means operable for changing the condition of said circuit, said switch means requiring actuation before said instrument can be ,moved substantially from its operative attached position on saidjbase, and means electrically con- F necting said switch means to said circuit for controlling the effectiveness of said contact means.

2. In an instrument unit, a detachable electrical relay instrument having circuit controlling contact means, a base for detachably receiving said instrument, a lock for preventing removal of said instrument from said base, a switch, means connecting said switch in circuit with said contact means, and means responsive to the actuation and release of said lock for operating said switch to control the eflectiveness of said contact means, said operating means including means for actuating and releasing said lock.

3. In a relay unit, a detachable relay having circuit controlling contact means subject to operation by shock, a base for detachably receiving said relay, a trip circuit controlled by said relay,

a circuit interrupting device connected to said trip circuit for controlling the effectiveness of said relay on said trip circuit, and actuating asses means for said circuit interrupting device, said actuating means including means positioned in the path of travel of said relay relative to said base for assuring actuation of said circuit interrupting device to a predetermined position prior to substantial movement of said relayfrom its mounted position on said base.

4: In an instrument assembly, a detachable electrical relay instrument having circuit controlling contact means, supporting means for detachably supporting said instrument in an operative position, said detachable instrument and supporting means having cooperating detachable electrical contact means, means cooperating with 1 said supporting means and instrument for forcing said detachable instrument towards and away from its operative position relative to said supporting means, second circuit controlling means responsiveto the condition of said last-named means, and means connecting the contact means of said instrument and said second circuit controlling means in a circuit wherein the condition of d second circuit controlling means detersaid instrument to control the circuit.

5. In an instrument unit, a detachable electrical relay instrument having circuit controlling means, a base for detachably receiving said instrument, securing means for retaining said instrument on said base, a switch operable between a plurality of positions, means connecting said switch in circuit with said circuit controlling means. and operating means for said switch pomines the effectiveness of the contact means of sitioned' for movement through a path normally occupied by said securing means, said operating means being biased ior movement into said path to operate said switch in response to removal of saidsecurlng means from said path.

c. In a relay unit, a detachable relay having' circuit controlling means, a base for detachably receiving said relay. a lock-controlled bolt for normally preventing removal of said relay from its base, a lock-controlled switch having s normal operating position, means for operating said bolt and said switch, said means being operable to move said bolt tor releasingsaid relay only when said switch is actuated away from said normal operating position, and means connecting said switch in circuit with said circuit controlling means for controlling a'circuit.

I. In an instrument assembly, a detachable redetachably receiving said instrument, a switch having a movable actuating element on said base. means electrically connecting said switch to said contact means for controlling the circuit, controlling eflectiveness of said contact means, and

a fastening element extending between'said instrument and said actuating element, said fastening element including for actuating said switch to render said contact m ineffective prior to the release of said rument by said fastening element, said actuating being operable for urging said instant towards said contact means for controlling the circuit controlling eflectiveness oi said contact means, and

a fastening element extending between said. instrument and said actuating element, said fastening element including means for actuating said switch to render said contact means ineflective prior to the release of said instrument by said.

fastening element, and said actuating means being operable for said instrument away from said base. V

9. In a protective device, a detachable relay having circuit controlling means, a base for detachably receiving said relay, cooperating detachable contact .means on said relay and said base, means including a current transformer for energizing said relay through said contact means,

a trip circuit for operation by the circuit con-' trolling means of said relay, means for opening said trip circuit, means for securing said relay against substantial detachment from said basev until saidtrip circuit opening means is actuated to a predetermined condition, and means responsive to detachment of said relay for establishing an auxiliary electrical circuit for said ,transformer.

10. In an electrical relay assembly, an electrical circuit, first electrical contact means associated with said electrical circuit, second electrical contact means associated with saidelectrical circuit, said first and second electrical contact means be-- ing actuable into and out of operative relationship relative to each other for changing the condition of said electrical circuit, a base, a relay unit detachably mounted on said base and having contact means for controlling said electrical circuit, means connecting the contact means of a detachable said relay unit in circuit with said first and second contact means for jointly controlling said electrical circuit, and means permitting substantial movement or said relay unit from said base only after said first and second contact means have been actuated out of operative relationship relative to each other.

ll. In an electrical relay assembly, a detachable electrical relay having circuit controlling means, a base for detachably receiving said relay, first contact means carried by said base, secand contact means carried by said relay, movable means movable from a first position in the path of detachment 01' said electrical relay when said electrical relay is in operative position on said base to a position clear of said path of detachment, electrical connecting means responsive to movement of said movable means for establishing an electrical connection between said first and second contact means only when said movable means is substantially in said first position, and means connecting said circuit controlling means in a circuit with said contact means wherein the establishment of said electrical connection controls the effectiveness of said circuit controlling means.

CHARLES P.

ROY M. SMITH.

WILLIAM A. LEWIS, JR.

DISCLAIMER 2,286,044..-Oharles P. West, Forest Hills, Pa., Roy M. Smith, Livingston, N. J.., and William A. Lewis, J12, Ithaca, N. Y. DETACHABLE RELAY. Patent dated June 9, 1942. Disclaimer filed March 30, 1944, by the inventors; the assignee, Westinghouse Electric dc Manufacturing Company, concurring.

, Hereby enter this disclaimer to claims 1, 3, 10, and 11- of said Letters Patent.

[Ofl'icial Gazette April 25, 1944.]

DlSCL AXMER 2,286,044.O'harles P. West, Forest Hills, Pa., Roy M. Smith, Livingston, N. J., and William A. Lewis, Jr., Ithaca, N. Y. DETACHABLE RELAY. Patent dated June 9, 1942. Disclaimer filed March 30, 1944, by the inventors; the assignee, Westinghouse Electric &: Manufacturing Company, concurring.

Hereby enter this disclaimer to claims 1, 3, 10,-and 11-,of said Letters Patent;

[Oflic'ial Gazette April 25, 1944.] 

